Solid-state image pickup apparatus and electronic apparatus

ABSTRACT

A solid-state image pickup apparatus includes a pixel region in which a plurality of pixels each including a photoelectric conversion element are arranged, transfer wirings formed on the pixel region in parallel to each other with uniform opening widths, and different wirings formed in a wiring layer above the transfer wirings. At least a part of the different wirings is overlapped with the transfer wirings on a plan position. The transfer wirings and the different wirings form a light shielding structure in the pixel region.

BACKGROUND

The present disclosure relates to a solid-state image pickup apparatusand an electronic apparatus.

A CMOS (complementary metal oxide semiconductor) solid-state imagepickup apparatus known as a solid-state image pickup apparatus involvesa low power source voltage and low power consumption. Therefore, theCMOS solid-state image pickup apparatus is used for a digital stillcamera, a digital video camera, and various mobile terminal apparatusessuch as a camera-equipped cellular phone, for example.

The CMOS solid-state image pickup apparatus is provided with pixelsconstituted of photodiodes serving as photoelectric conversion units anda plurality of pixel transistors. Further, the CMOS solid-state imagepickup apparatus includes a pixel unit in which a plurality of pixelsare arranged in a two-dimensional array form and a peripheral circuitunit disposed on the periphery of the pixel unit.

Further, these days, attention is being focused on a back surfaceirradiation type CMOS solid-state image pickup apparatus (see, JapanesePatent Application Laid-open Nos. 2007-115994 and 2003-31785). The backsurface irradiation type CMOS solid-state image pickup apparatus has alight incident surface on an opposite side (back surface of substrate)to a side on which a wiring is provided (front surface of substrate).Therefore, it is possible to provide the wiring of a pixel unit on aphotodiode, with the result that the degree of freedom of a layout isdramatically increased.

Furthermore, along with achieving of a finer pixel size, a CMOSsolid-state image pickup apparatus of a pixel sharing type in which aplurality of photodiodes are caused to share a pixel transistor groupexcluding a transfer transistor is also known (see, Japanese PatentApplication Laid-open Nos. 2008-294218 and 2009-135319).

SUMMARY

In the back surface irradiation type CMOS solid-state image pickupapparatus described above, when an interval between adjacent wiringsbecomes smaller as the pixel size becomes finer, capacitive couplingbetween the wirings does not become negligible. In a transfer wiring, apulse voltage supplied to a transfer gate varies due to an influence ofanother wiring. In particular, if an off-state voltage that is suppliedto the transfer gate varies, a potential in a substrate under thetransfer gate varies. The potential variation causes charges accumulatedin the photodiodes to leak into a floating diffusion (FD), which causesproblems of a change in saturation signal amount (Qs), an increase invariation of the saturation signal amount between the photodiodes, andthe like. In this way, if the variation in the saturation signal amountis large for each pixel, the image quality of the solid-state imagepickup apparatus degrades.

In view of the above-mentioned circumstances, it is desirable to providea solid-state image pickup apparatus and an electronic apparatus havingsuch a structure that the quality of images can be upgraded.

According to an embodiment of the present disclosure, there is provideda solid-state image pickup apparatus including a pixel region in which aplurality of pixels each including a photoelectric conversion elementare arranged, transfer wirings formed on the pixel region in parallel toeach other with uniform opening widths, and different wirings formed ina wiring layer above the transfer wirings. At least a part of thedifferent wirings is overlapped with the transfer wirings on a planposition, and the transfer wirings and the different wirings form alight shielding structure in the pixel region.

According to another embodiment of the present disclosure, there isprovided an electronic apparatus including the solid-state image pickupapparatus and a signal processing circuit configured to process anoutput signal of the solid-state image pickup apparatus.

With the solid-state image pickup apparatus described above, thetransfer wirings are arranged in parallel to each other with uniformopening widths. Therefore, the coupling capacitance between the transferwirings becomes constant, and a variation of a saturation signal amountbetween pixels becomes constant. Thus, the saturation signal amountbetween the pixels is equalized, with the result that the image qualityof the solid-state image pickup apparatus can be upgraded.

Further, with the use of the solid-state image pickup apparatus, it ispossible to upgrade the image quality of the electronic apparatus.

According to the present disclosure, it is possible to provide thesolid-state image pickup apparatus and the electronic apparatus that canupgrade the image quality.

These and other objects, features and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription of best mode embodiments thereof, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view showing the structure of a solid-state imagepickup apparatus according to a first embodiment of the presentdisclosure;

FIGS. 2A and 2B are schematic diagrams each showing the structure of thesolid-state image pickup apparatus;

FIG. 3 is a cross-sectional view showing the structure of thesolid-state image pickup apparatus according to the first embodiment;

FIGS. 4A and 4B are a cross-sectional structure and a plan structure ofwiring layers, respectively;

FIG. 5 is a diagram showing the structure of a pixel structure of a 4pixel sharing unit;

FIGS. 6A is a plan view showing the structure of a light shieldingstructure of the solid-state image pickup apparatus according to thefirst embodiment, and FIG. 6B is a cross-sectional view of wiring layersthat constitute the light shielding structure;

FIG. 7A is a plan view showing the structure of a light shieldingstructure of a solid-state image pickup apparatus according to a secondembodiment, and FIG. 7B is a cross-sectional view of wiring layers thatconstitute the light shielding structure;

FIG. 8A is a plan view showing the structure of a light shieldingstructure of a solid-state image pickup apparatus according to a thirdembodiment, and FIG. 8B is a cross-sectional view of wiring layers thatconstitute the light shielding structure;

FIG. 9A is a plan view showing the structure of a light shieldingstructure of a solid-state image pickup apparatus according to a fourthembodiment, and FIG. 9B is a cross-sectional view of wiring layers thatconstitute the light shielding structure; and

FIG. 10 is a diagram showing the structure of an electronic apparatus.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present disclosure will be describedwith reference to the drawings.

It should be noted that the description will be given in the followingorder.

1. Outline of solid-state image pickup apparatus

2. First embodiment of solid-state image pickup apparatus

3. Second embodiment of solid-state image pickup apparatus

4. Third embodiment of solid-state image pickup apparatus

5. Fourth embodiment of solid-state image pickup apparatus

6. Electronic apparatus

<1. Outline of Solid-State Image Pickup Apparatus>

Hereinafter, the outline of a solid-state image pickup apparatus will bedescribed.

In general, in a back surface irradiation type CMOS solid-state imagepickup apparatus, a horizontal overflow structure is formed as acountermeasure against blooming. In the horizontal overflow structure,charges are caused to escape from below a transfer gate through afloating diffusion. Therefore, in the back surface irradiation type CMOSsolid-state image pickup apparatus, due to an influence of thehorizontal overflow structure, the potential at the transfer gate islikely to vary. In this way, in a transfer wiring that supplies a pulsevoltage to the transfer gate, due to the influence of capacitivecoupling between wirings, the change in saturation signal amount (Qs) oran increase in variation in the saturation signal amount between thephotodiodes may be caused, for example.

To suppress the variation in the saturation signal amount, it isnecessary to uniform the potential variation of the transfer gate. Ifthe potential variation of the transfer gate is uniform, the variationin the potential in a substrate under the transfer gate is equalized,with the result that the variation in the saturation signal amount iseliminated.

To make the potential variation of the transfer gate uniform, a responsein a viewpoint of a wiring arrangement in a pixel unit is necessary. Inview of this, by devising the wiring arrangement in the pixel unit, thecoupling capacitance of the transfer wiring and another wiring isequalized. Thus, if the coupling capacitance can be equalized, thepotential variation of the transfer wiring is equalized in each transfergate. Therefore, it is possible to suppress the variation in thesaturation signal amount.

On the other hand, in the solid-state image pickup apparatus, as amethod for downsizing a plurality of chips and a plurality of functions,such an effort that the plurality of chips are bonded to each other tomake a high-speed transfer possible is started. In this case, aphotoelectric conversion element unit and a peripheral circuit unit areformed so as to be very close to each other, so a problem inherent in animage sensor is caused. A photoelectric conversion element uses finecarriers (electrons) as signals, so an influence of heat or anelectromagnetic field from a circuit therearound tends to be mixedtherein as a noise. In addition, minute hot carrier light emission,which is negligible in a normal circuit operation of a transistor or adiode, significantly affects the characteristics of the image sensor.

The hot carrier light emission is caused by generating and recouplingholes and electrons that are generated at a time when carriersaccelerated between a source and a drain are subjected to collisionalionization at a drain corner or by causing a state transition of eitherone. The light is generated minutely but steadily even in a transistorhaving no problem in characteristics. The light is diffused in alldirections, so an influence thereof becomes smaller at a distance.However, in the case where the photoelectric conversion element and acircuit are disposed very closely, the light is not diffused very much,and photons are considerably implanted into the photoelectric conversionelement.

In this way, the diffusion of the hot carrier light is insufficient, soa generation distribution of the hot carrier light due to a differencein an active rate or a transistor disposition density of the circuitgets in an image as two-dimensional information. To deal with this, itis necessary to provide a light shielding structure for keeping theamount of implantation in the photoelectric conversion element below adetection limit.

In related art, to suppress the variation in the saturation signalamount, by devising the arrangement of the wirings in the pixel unit,the coupling capacitance of the transfer wiring and another wiring isequalized.

In the case where the wiring arrangement in related art is used,however, one or more gaps are generated between adjacent wirings, andtherefore it is necessary to additionally prepare a light shieldingstructure to suppress the influence of the hot carrier light emission asdescribed above.

In the case where the light shielding structure is formed byadditionally providing a light shielding film, the light shielding filmis made of a material such as W, Cu, Ti, TiN, and C. An absorption filmmay be formed by using a material that absorbs light instead of thelight shielding film. However, both of the cases have demerits in termsof the cost and the like.

In view of this, in this embodiment, a wiring structure is providedwhich is capable of achieving the equalization of the couplingcapacitance and the light shielding structure without additionallyproviding a new structure for light shielding.

<2. First Embodiment of Solid-State Image Pickup Apparatus>

(Schematic Structure of Solid-State Image Pickup Apparatus)

FIG. 1 is the schematic structure of a MOS solid-state image pickupapparatus which is applied to a solid-state image pickup apparatus ofthis embodiment. The MOS solid-state image pickup apparatus is appliedto a solid-state image pickup apparatus of each embodiment. Asolid-state image pickup apparatus 1 in this embodiment includes asemiconductor substrate (not shown), a pixel region (so-called pixelarray) 3 in which pixels 2 including a plurality of photoelectricconversion units are arranged in a regular two-dimensional array patternon the semiconductor substrate (not shown), for example, on a siliconsubstrate, and a peripheral circuit unit. The pixel 2 includes aphotodiode serving as the photoelectric conversion unit and a pluralityof pixel transistors (so-called MOS transistors), for example.

The plurality of pixel transistors can be constituted of threetransistors of a transfer transistor, a reset transistor, and anamplification transistor, for example. Further, a selection transistorcan be added thereto, and thus the four transistors can constitute thepixel transistors. An equivalent circuit of a unit pixel is the same asa normal case, so a detailed description thereof will be omitted. Thepixel 2 can be formed as one unit pixel. Further, the pixel 2 can alsobe a pixel sharing structure. The pixel sharing structure is thestructure in which the plurality of photodiodes share transistorsexcluding the transfer transistor and the floating diffusion that formsthe transfer transistor.

The peripheral circuit unit includes a vertical drive circuit 4, columnsignal processing circuits 5, a horizontal drive circuit 6, an outputcircuit 7, a control circuit 8, and the like.

The control circuit 8 receives data for giving an instruction of anoperation mode or the like and an input clock and outputs data such asinternal information of the solid-state image pickup apparatus. That is,in the control circuit 8, on the basis of a vertical synchronizationsignal, a horizontal synchronization signal, and a master clock, a clocksignal and a control signal as a reference of an operation of thevertical drive circuit 4, the column signal processing circuits 5, andthe horizontal drive circuit 6, and the like is generated. The signalsare input to the vertical drive circuit 4, the column signal processingcircuits 5, and the horizontal drive circuit 6, and the like.

The vertical drive circuit 4 is formed of a shift register, for example,and selects a pixel drive wiring, supplies pulses for driving pixels tothe pixel drive wiring selected, and drives pixels in the unit of a row.In other words, the vertical drive circuit 4 performs selection scanningfor the pixels 2 in the pixel area 3 in the unit of a row sequentiallyin a vertical direction, and supplies, to the column signal processingcircuit 5, a pixel signal based on a signal charge generated inaccordance with a reception light quantity in the photodiode or the likeas the photoelectric conversion unit of the pixels 2 through a verticalsignal line 9.

The column signal processing circuit 5 is provided for each of columnsor the like of the pixels 2 and performs signal processing of a noiseremoval or the like for each pixel column with respect to a signaloutput from the pixels 2 of one column. That is, the column signalprocessing circuit 5 performs signal processing such as a CDS forremoving a fixed pattern noise inherent in the pixels 2, signalamplification, and an AD conversion. On an output stage of the columnsignal processing circuit 5, a horizontal selection switch (not shown)is connected with a horizontal signal line 10.

The horizontal drive circuit 6 is formed of a shift register or thelike, sequentially outputs horizontal scanning pulses, thereby selectingthe column signal processing circuits 5 in order, and causes each of thecolumn signal processing circuits 5 to output a pixel signal to thehorizontal signal line 10.

The output circuit 7 performs signal processing for signals sequentiallysupplied from the column signal processing circuits 5 through thehorizontal signal line 10 and outputs the signals. For example, onlybuffering may be performed, or a black level adjustment, a columnvariation correction, various digital signal processing, and the likemay be performed. An input and output terminal 12 is used to transmitand receive signals to and from outside.

Next, the structure of the MOS solid-state image pickup apparatusaccording to this embodiment will be described. FIGS. 2A and 2B areschematic structural diagrams each showing the structure of the MOSsolid-state image pickup apparatus according to this embodiment.

As shown in FIG. 2A, in a MOS solid-state image pickup apparatus 21 inthis example, a pixel region 23 is mounted on a first semiconductor chipunit 22, and a control circuit 24 and a logic circuit 25 including asignal processing circuit are mounted on a semiconductor chip unit 26.The first semiconductor chip unit 22 and the second semiconductor chipunit 26 are electrically connected with each other, thereby forming theMOS solid-state image pickup apparatus 21 as one semiconductor chip.

As shown in FIG. 2B, in a MOS solid-state image pickup apparatus 27 inan example, the pixel region 23 and the control circuit 24 are mountedon the first semiconductor chip unit 22, and the logic circuit 25including the signal processing circuit for performing signal processingis mounted on the second semiconductor chip unit 26. The firstsemiconductor chip unit 21 and the second semiconductor chip unit 26 areelectrically connected with each other, thereby forming the MOSsolid-state image pickup apparatus 27 as one semiconductor chip.

Although not shown, in a MOS solid-state image pickup apparatus inanother example, on the first semiconductor chip unit 22, the pixelregion 23 and a control circuit unit which is suitable for control ofthe pixel region as a part of the control circuit are mounted. Further,on the second semiconductor chip unit 26, the logic circuit 25 and acontrol circuit unit which is suitable for control of the logic circuitas another part of the control circuit are mounted. The firstsemiconductor chip unit 22 and the second semiconductor chip unit 26 areelectrically connected with each other, thereby forming the MOSsolid-state image pickup apparatus 27 as one semiconductor chip.

The MOS solid-state image pickup apparatus in the above example has thestructure in which semiconductor chips of different kinds are layeredand has a characteristic thereof in the structure to be described later.

(Cross-Sectional Structure of Solid-State Image Pickup Apparatus)

FIG. 3 shows the solid-state image pickup apparatus, in particular, theMOS solid-state image pickup apparatus according to the firstembodiment. The MOS solid-state image pickup apparatus according to thisembodiment is a back surface irradiation type solid-state image pickupapparatus. To the MOS solid-state image pickup apparatus according tothis embodiment, the structure shown in FIG. 2B is applied, but thestructure shown in FIG. 2A or the structure in which the control circuitis mounted separately on the first and second semiconductor chip unitscan also be applied. In a second embodiment and embodiments subsequentthereto, the structures can be applied in the same way.

The solid-state image pickup apparatus according to the first embodimentis formed by bonding a first semiconductor chip unit 31 and a secondsemiconductor chip unit 45 to each other. On the first semiconductorchip unit 31, a pixel array (hereinafter, referred to as pixel region23) in which a photodiode PD serving as a photoelectric conversion unitand pixels constituted of a plurality of pixel transistors aretwo-dimensionally arranged and a control circuit 24 are formed.

The photodiode PD has an n-type semiconductor region 34 in asemiconductor well region 32 and a p-type semiconductor region 35 on thesurface side of a substrate. On the surface of the substrate that formsthe pixels, a gate electrode 36 is formed through a gate insulatingfilm, and a source and drain region 33 that forms a pair with the gateelectrode 36 forms pixel transistors Tr1 and Tr2. In FIG. 3, the twopixel transistors Tr1 and Tr2 are shown so as to be representative ofthe plurality of pixel transistors. The pixel transistor Tr1 adjacent tothe photodiode PD corresponds to the transfer transistor, and the sourceand drain region thereof corresponds to the floating diffusion FD. Unitpixels are isolated by an element isolation region 38.

On the other hand, the control circuit 24 is constituted of a pluralityof MOS transistors formed in the semiconductor well region 32. In FIG.3, the plurality of MOS transistors that constitute the control circuit24 are represented by MOS transistors Tr3 and Tr4. The MOS transistorsTr3 and Tr4 are each formed by n-type source and drain region 33 and thegate electrode 36 formed through the gate insulating film.

On the side of the front surface of the substrate, a multilayer wiringlayer 41 formed by arranging wirings 40 for a plurality of layersthrough an interlayer insulating film 39. The wiring 40 is formed of acopper wiring, for example. The pixel transistor and the MOS transistorof the control circuit are connected to a necessary wiring 40 through aconnected conductor 44 that penetrates a first insulating film 43 a anda second insulating film 43 b. The first insulating film 43 a is formedof a silicon oxide film, for example, and the second insulating film 43b is formed of a silicon nitride film, for example, that serves as anetching stopper.

On the back surface of the semiconductor well region 32, anantireflection film 61 is formed. On a region on the antireflection film61 which corresponds to each of the photodiodes PD, a waveguide 70formed of a waveguide material film (for example, SiN film) 69 isformed. In an insulating film 62 formed of a SiO film or the like on theback surface of the semiconductor well region 32, a light shielding film63 that shields light with respect to a necessary area. Further, a colorfilter 73 and an on-chip micro lens 74 are formed through a flatteningfilm 71 so as to correspond to each of the photodiodes PD.

On the other hand, on the semiconductor chip unit 45, a logic circuit 25including a signal processing circuit for performing signal processingis formed. The logic circuit 25 is formed by forming a plurality of MOStransistors in, for example, a p-type semiconductor well region 46 so asto be isolated by an element isolation region 50. In this case, theplurality of MOS transistors are represented by MOS transistors Tr6,Tr7, and Tr8. The MOS transistors Tr6, Tr7, and Tr8 each have a pair ofn-type source and drain region 47 and a gate electrode 48 formed throughthe gate insulating film.

On the semiconductor well region 46, a multilayer wiring layer 55 isformed in which a wiring 53 in a plurality of layers and a wiring 57having a barrier metal layer 58 are disposed through an interlayerinsulating film 49. The MOS transistors Tr6, Tr7, and Tr8 are eachconnected to the necessary wiring 53 through a connected conductor 54that penetrates the first insulating film 43 a and the second insulatingfilm 43 b.

The first semiconductor chip unit 31 and the second semiconductor chipunit 45 are bonded to each other with an adhesive layer 60 or the likeso that the multilayer wiring layers 41 and 55 thereof face each other.On a bonded surface of the multilayer wiring layer 55 on the side of thesecond semiconductor chip unit 45, a stress correction film 59 forreducing a bonding stress is formed. The bonding can also be performedby plasma bonding.

Further, the first semiconductor chip unit 31 and the secondsemiconductor chip unit 45 are electrically connected through aconnected conductor 68. That is, a connection hole is formed whichpenetrates the semiconductor well region 32 of the first semiconductorchip unit 31 and reaches the necessary wiring 40 of the multilayerwiring layer 41. Further, a connection hole is formed which penetratesthe semiconductor well region 32 of the first semiconductor chip unit 31and the multilayer wiring layer 41 and reaches the necessary wiring 53of the multilayer wiring layer 55. The connected conductor 68 that areconnected to those connection holes are buried, thereby electricallyconnecting the first semiconductor chip unit 31 and the secondsemiconductor chip unit 45. An insulating film 67 surrounds theconnected conductor 68 therearound so that the connected conductor 68 isinsulated from the semiconductor well region 32. The wirings 40 and 57that are connected to the connected conductor 68 correspond to verticalsignal lines. The connected conductor 68 is connected to an electrodepad (not shown) or may be set as an electrode pad.

The connected conductor 68 is formed after the semiconductor chip unit31 and the second semiconductor chip unit 45 are bonded to each other,and then the semiconductor well region 32 of the first semiconductorchip unit 31 is thinned. After that, a cap film 72, the flattening film71, the color filter 73, and the on-chip micro lens 74 are formed. Inthe semiconductor well region 32, an insulating spacer layer 42 isformed around the connected conductor 68.

In this embodiment, a light shielding structure is formed by wiring inan area that covers the pixel region with no space and is between thephotodiode PD of the pixel region 23 and the logic circuit 25.

For example, in the solid-state image pickup apparatus, in themultilayer wiring layer 41 of the photoelectric conversion element ofthe pixel region, the wiring 40 is disposed so as to cover the pixelregion with no space. At this time, by using two or more wiring layers,the wirings 40 are overlapped with each other to some extent, with theresult that it is possible to prevent a light diffraction influence andsuppress incident light from a lower portion.

Further, to equalize the coupling capacitance, in the light shieldingstructure, transfer wirings disposed at equal intervals in the samelayer and other wirings disposed in a different layer so as to beoverlapped with the transfer wirings to a certain degree are combined.With this structure, it is possible to form the light shieldingstructure that shields light radiated at the time of an operation of anactive element of the peripheral circuit unit only by the wiring layerswithout additionally providing a layer for light shielding. With thisstructure, it is possible to prevent the hot carrier light from enteringthe photodiode PD of the pixel. As the active element, a MOS transistor,a protection diode, or the like is used.

(Light Shielding Structure by Wiring)

FIGS. 4A and 4B each show a structural example of the light shieldingstructure by the wiring. FIG. 4A is a diagram showing a cross-sectionalview of the wiring layer, and FIG. 4B is a diagram showing a plan viewof the wiring layer.

At least two layers of a wiring 40A and a wiring 40B constitute thelight shielding structure.

In the light shielding structure, a lamination interval between thewiring 40A on a lower layer and the wiring 40B on an upper layer is setas a distance 81. In the same way, a length by which the wiring 40A onthe lower layer and the wiring 40B on the upper layer are overlappedwith each other in a plane direction is set as an overlap amount 82. Aninterval between the wirings 40A on the lower layer is set as an openingwidth 83.

The overlap amount 82 is defined by the distance 81 and the openingwidth 83 between the wirings. The hot carrier light is generated as apoint light source, so it is necessary to shield light that is incidentobliquely. The overlap amount 82 is set to be larger than at least thedistance 81 between the wirings, with the result that the lightshielding performance for the hot carrier light in an oblique directionis increased.

Further, the opening widths 83 of the wirings between the wirings 40Aformed in the same layer are set to be equal. Furthermore, the overlapamounts 82 are uniformly formed. With this structure, the positionalrelationship between the wirings 40A and 40B can be equalized, andtherefore the coupling capacitance can be equalized.

(Pixel Sharing Unit: Pixel Structure)

Next, a description will be given on the structure of a pixel unit thatis applied to the solid-state image pickup apparatus according to thisembodiment. FIG. 5 shows the structure of the pixel unit formed of a 4pixel sharing unit, which is applied to this embodiment. As shown inFIG. 5, the 4 pixel sharing unit in which the photodiodes PD (PD1 toPD4) of four pixels are arranged is disposed in a two-dimensional arrayform, thereby forming the pixel unit.

The 4 pixel sharing unit has the structure in which one floatingdiffusion FD is shared by the four photodiodes PD (two in a horizontaldirection and two in a vertical direction). The unit includes fourphotodiodes PD1 to PD4, transfer gate electrodes 75 to 78 for thephotodiodes PD1 to PD4, respectively, and the one floating diffusion FD.The photodiodes PD1 to PD4, the floating diffusion FD, and the transfergate electrodes 75 to 78 constitute transfer transistors Tr11 to Tr14,respectively. The floating diffusion FD is disposed on a center portionsurrounded by the four photodiodes PD1 to PD4, and the transfer gateelectrodes 75 to 78 are disposed on positions corresponding to cornerportions of the photodiodes PD1 to PD4 on the side of the centerportion, respectively.

In addition, in FIG. 5, above the 4 pixel sharing unit, a selectiontransistor Tr23 and an amplification transistor Tr22 are disposed. Belowthe 4 pixel sharing unit, a reset transistor Tr21 is disposed. Theselection transistor Tr23 includes a pair of source and drain regions 94and 95 and a selection gate electrode 79. The amplification transistorTr22 includes a pair of source and drain regions 95 and 96 and anamplification gate electrode 80. The reset transistor includes a pair ofsource and drain regions 97 and 98 and a reset gate electrode 99. Thegate electrodes are each formed of a polysilicon film. The FD1 isconnected to the amplification gate electrode 80 of the amplificationtransistor Tr23 and the source region of the reset transistor Tr21.

In the wiring layer of a region in which the photodiodes PD are formed,the light shielding structure described above is formed. It is desirablethat the light shielding region by the wiring layer entirely covers theregion in which the photodiodes PD are formed.

However, if the region in which the photodiodes PD are formed is notentirely covered, it is possible to obtain the effect of the lightshielding structure. For example, like a light shielding region 100shown in FIG. 5, it is desirable to perform light shielding for a squareregion including at least a short side of the photodiode PD1 as oneside. In the same way, for each of the photodiodes PD2 to PD4, a squareregion including a short side of each of the photodiodes PD2 to PD4 asone side is subjected to the light shielding. By forming the lightshielding structure is formed by wiring on the light shielding region100, it is possible to obtain a sufficient light shielding effect. Inthis way, in the case where the light shielding layer that partiallycovers the region of the photodiode PD is provided without entirelycovering the region in which the photodiode PD is formed, it is alsopossible to obtain the effect of the light shielding structure.

(Structure of Wiring: Structural Example of Light Shielding Structure)

Next, a description will be given on the light shielding structure bythe wiring layer, which is provided on the pixel unit in which the 4pixel sharing unit is formed described above.

As shown in FIG. 3, in the back surface irradiation type CMOSsolid-state image pickup apparatus, on the front surface side of thesemiconductor substrate, a pixel transistor is formed, and the wiringlayer in which wirings of the plurality of layers formed of metal layersare disposed through the interlayer insulating film is formedthereabove. On the back surface side of the semiconductor substrate, thecolor filter layer and the on-chip lens are formed, and light enters theback surface of the substrate. That is, the back surface irradiationtype has the structure in which the wiring layers are formed on theopposite side to the light incident surface.

FIG. 6 shows the light shielding structure formed on the pixel unitaccording to the first embodiment. FIG. 6A is a plan view showing thestructure of various wirings formed on the 4 pixel sharing unit. FIG. 6Bis a cross-sectional view of the wiring structure shown in FIG. 6A takenalong the line A-A. Further, the pixel unit of the 4 pixel sharing unitshown in FIG. 6A has the same structure as that shown in FIG. 5. Thesame parts are denoted by the same reference symbols, and a detaileddescription thereof will be omitted.

The wirings that form the light shielding structure on the pixel unitincludes a transfer wiring and other wirings arranged in parallel to thetransfer wiring. In this embodiment, as the wirings disposed in parallelto the transfer wiring, a pulse wiring and a dummy wiring are used. Thewirings other than the transfer wiring are not particularly limited, andvarious wirings provided in the CMOS solid-state image pickup apparatus,dummy wirings, or the like can be used as appropriate.

As shown in FIG. 6A, in the pixel unit, transfer wirings 84 to 87 whichare extended in a horizontal direction when viewed from above andarranged in a vertical direction in parallel to each other are arrangedat necessary intervals. For example, out of the four transfer wirings 84to 87, at least one transfer wiring is disposed across the photodiodePD. In this example, transfer wirings 84 and 87 are formed across thevicinity of the center of the photodiodes PD.

The transfer wirings 84 to 87 are connected to the transfer gateelectrodes 75 to 78 of the transfer transistors Tr11 to Tr14 of the 4pixel sharing unit. At this time, it is desirable that the four transferwirings 84 to 87 have the same wiring width and the same wiringinterval.

Further, as shown in FIG. 6A, pulse wirings 88 to 91 are provided so asto be adjacent to the four transfer wirings 84 to 87. In FIGS. 6A and6B, besides the transfer wirings 84 and 87 provided on the outer side,the pulse wirings 88 and 89 and the pulse wirings 90 and 91 areprovided, respectively. The pulse wirings 88 to 91 are arranged so as tobe in parallel to the transfer wirings 84 to 87. It is desirable thatthe pulse wirings 88 to 91 and the transfer wirings 84 to 87 have thesame wiring width and the same wiring interval.

As shown in FIG. 6B, in the first embodiment, the wirings including thetransfer wirings 84 and 87 and the pulse wirings 88 to 91 are formed inthe same wiring layer.

Furthermore, as shown in FIG. 6A and 6B, in a wiring layer differentfrom the wiring layer in which the transfer wirings 84 and 87 and thepulse wirings 88 to 91 are formed, dummy wirings 92 are formed. As shownin FIGS. 6A and 6B, the dummy wirings 92 are disposed so as to beoverlapped with the transfer wirings 84 to 87 and the pulse wirings 88to 91. The dummy wirings 92 may be electrically floated or may be fixedto a power source voltage and a ground.

In the light shielding structure according to the first embodiment, inthe multilayer wiring layer, the transfer wirings 84 to 87 and the pulsewirings 88 to 91 are provided in a lower wiring layer, and the dummywirings 92 are provided in an upper wiring layer.

Like the wirings 40A and 40B shown in FIGS. 4A and 4B mentioned above,the transfer wirings 84 to 87 and the pulse wirings 88 to 91 in thelower layer and the dummy wirings 92 in the upper layer have the overlapamount 82 larger than the distance 81 between the wirings of the wiringlayer.

Further, the opening widths 83 of the transfer wirings 84 to 87 and thepulse wirings 88 to 91 are formed to be uniform. Furthermore, theopening widths 83 of the dummy wirings 92 are formed to have a certainlength.

The transfer wirings 84 to 87, the pulse wirings 88 to 91, and the dummywirings 92 are disposed as described above, with the result that a lightshielding structure is formed between the photodiodes PD and the activeelements such as a logic circuit disposed to be close to the photodiodesPD. Therefore, it is possible to shield hot carrier light generated inthe MOS transistor of the logic circuit or the like by the wiring layerthat forms the light shielding structure. In addition, it is alsopossible to shield light generated when a diode for protection isoperated by the wiring layer that forms the light shielding structure.Thus, it is possible to prevent the hot carrier light from entering thephotodiodes PD of the pixel unit.

In particular, the transfer wirings 84 to 87 and pulse wirings 88 to 91and the dummy wirings 92 have the overlap amounts 82 larger than thedistances 81 between the wirings, with the result that it is possible toshield diagonally incident hot carrier light due to the influence of thediffraction of light. Therefore, it is possible to provide the lightshielding structure capable of further suppressing the hot carrier lightthat enters the photodiodes PD.

As a result, it is possible to avoid causing the hot carrier light toenter the pixel region and thus provide the solid-state image pickupapparatus the image quality of which is upgraded.

Further, the transfer wirings 84 to 87 and pulse wirings 88 to 91 andthe dummy wirings 92 have the opening widths 83 which are uniform, withthe result that it is possible to set positional relationship betweenthe wirings to be the same. Therefore, it is possible to equalize thecoupling capacitance between the wirings and equalize the potentialvariation of the transfer gates.

As a result, the potential variation of the transfer wirings becomes thesame for each transfer gate, which can suppress the variation of thesaturation signal amounts of the pixels.

<3. Second Embodiment of Solid-State Image Pickup Apparatus>

Next, the structure of a solid-state image pickup apparatus according toa second embodiment will be described. In the second embodiment, it isalso possible to apply the solid-state image pickup apparatus which isthe same as the first embodiment except the structure of wirings thatform a light shielding structure. Therefore, in the following, thestructure of the wirings that form the light shielding structure will bedescribed.

(Wirings: Structural Example of Light Shielding Structure)

FIGS. 7A and 7B each show a wiring structure that forms the lightshielding structure, which is provided on a pixel unit in which a pixelsharing unit is formed. FIG. 7A is a plan view showing the structure ofvarious wirings formed on the 4 pixel sharing unit shown in FIG. 5. FIG.7B is a cross-sectional view of the wiring structure taken along theline A-A of FIG. 7A.

The transfer wirings 84 to 87 and the pulse wirings 88 to 91 aredisposed as in the first embodiment. Above a wiring layer in which thetransfer wirings 84 to 87 and the pulse wirings 88 to 91 are formed, awiring layer in which the dummy wiring 92 is formed is provided.

The dummy wiring 92 covers the photodiodes PD of the 4 pixel sharingunit so as to cover the transfer wirings 84 to 87 and the pulse wirings88 to 91. It is desirable that a region where the dummy wiring 92 isformed is equal to or larger than the light shielding region shown inFIG. 5. In particular, it is desirable to form the dummy wiring 92 onthe entire surface of the pixel unit. The dummy wiring 92 may beelectrically floated or may be fixed to a power source voltage or aground.

Further, the transfer wirings 84 to 87 and the pulse wirings 88 to 91have the uniform opening widths 83 between the wirings shown in FIGS. 4Aand 4B. The dummy wiring 92 entirely covers the transfer wirings 84 to87 and the pulse wirings 88 to 91, so the overlap amount 82 is uniformfor each wiring. Further, the widths of the transfer wirings 84 to 87and the pulse wirings 88 to 91 are set to be larger than the distance 81between the wirings, thereby setting the overlap amount 82 to be largerthan the distance 81 between the wirings.

The transfer wirings 84 to 87, the pulse wirings 88 to 91, and the dummywiring 92 are disposed as described above, with the result that it ispossible to set positional relationship between wirings to be the same.Therefore, it is possible to equalize the coupling capacitance betweenthe wirings and equalize the potential variations of the transfer gates.Accordingly, the same influence of the potential variations of thetransfer wirings is provided, which can suppress the variation of thesaturation signal amounts between the photodiodes.

Further, the transfer wirings 84 to 87, the pulse wirings 88 to 91, andthe dummy wiring 92 are formed, with the result that the light shieldingstructure having the overlap amount 82 larger than the distance 81between the wirings on the pixel unit. Thus, it is possible to preventthe hot carrier light from entering the photodiodes PD of the pixelunit. The structure is particularly effective for the prevention ofdiagonally incident hot carrier light due to the influence of thediffraction of light.

<4. Third Embodiment of Solid-State Image Pickup Apparatus>

Next, the structure of a solid-state image pickup apparatus according toa third embodiment will be described. In the third embodiment, it isalso possible to apply the solid-state image pickup apparatus as in thefirst embodiment except the structure of wirings that form a lightshielding structure. Therefore, in the following, the structure of thewirings that form the light shielding structure will be described.

(Wirings: Structural Example of Light Shielding Structure)

FIGS. 8A and 8B each show a wiring structure that forms the lightshielding structure, which is provided on the pixel unit in which thepixel sharing unit is formed. FIG. 8A is a plan view showing thestructure of various wirings formed on the 4 pixel sharing unit shown inFIG. 5 mentioned above. FIG. 8B is a cross-sectional view of the wiringstructure taken along the line A-A of FIG. 8A.

As shown in FIGS. 8A and 8B, the transfer wirings 84 to 87 and the pulsewirings 88 to 91 are disposed in the same way as the first embodiment.Above the wiring layer in which the transfer wirings 84 to 87 and thepulse wirings 88 to 91 are formed, a wiring layer in which the dummywiring 92 is formed is provided.

The light shielding structure by the wirings according to the thirdembodiment is an example in which an opening portion is formed on a partof the light shielding structure. Therefore, the structure shown inFIGS. 8A and 8B has the opening portion on the pixel unit and outsidethe light shielding region of the photodiodes PD in addition to thelight shielding structure according to the second embodiment.

In this way, in the light shielding structure by the wirings, theopening portion may be formed on the pixel unit.

The dummy wiring 92 covers the photodiodes PD of the 4 pixel sharingunit so as to cover the transfer wirings 84 to 87 and the pulse wirings88 to 91. It is desirable that a region in which the dummy wiring 92 isformed is equal to or larger than the light shielding region shown inFIG. 5. In particular, it is desirable to form the dummy wiring 92 overthe entire pixel unit. The dummy wiring 92 may be electrically floatedor may be fixed to a power source voltage and a ground.

Further, in the dummy wiring 92, an opening portion 101 from which apart of the wiring is removed is formed. In the light shieldingstructure by the wirings, a region where an upper wiring layer and alower wiring layer do not have an overlap corresponds to the openingportion 101. That is, in the example of the third embodiment, a regionwhere the transfer wirings 84 to 87 and the pulse wirings 88 to 91 thatare formed in the lower wiring layer and the dummy wiring 92 is notformed in the upper wiring layer corresponds to the opening portion 101of the light shielding structure by the wirings.

It is difficult to partially remove the transfer wirings 84 to 87 andthe pulse wirings 88 to 91, so a part of the dummy wiring 92 is removed,thereby forming the opening portion 101.

It is desirable to form the opening portion 101 on a position excludingthe photodiodes PD of the pixel unit in order to shield the hot carrierlight generated in the MOS transistor disposed nearby. But, if anopening that does not affect an obtaining image of the solid-state imagepickup apparatus, for example, such an opening that only hot carrierlight of a detection limit or less is incident on the photodiodes PD isformed, the opening portion 101 may be provided on the photodiodes PD.

For example, on the photodiodes PD shown in FIG. 5, a square region thathas at least a side corresponding to a short side of the photodiode PDis the light shielding region 100.

Further, for example, a position where the opening portion 101 is formedand the number of opening portions 101 to be formed are not limited, aslong as the center of the opening is not on the photodiode PD.

The transfer wirings 84 to 87 and the pulse wirings 88 to 91 have suchpositional relationship that the opening widths 83 between wirings shownin FIGS. 4A and 4B are uniform. As long as the disposition of thetransfer wirings 84 to 87 and the pulse wirings 88 to 91 has uniformity,uniformity with the dummy wiring does not matter. In the region wherethe opening portion 101 is formed, the positional relationship betweenthe transfer wirings and the dummy wiring does not keep the uniformitywith other region, but the uniformity between the transfer wirings andthe dummy wiring has almost no influence on the coupling capacitance andthus may be negligible.

As described above, the transfer wirings 84 to 87 and the pulse wirings88 to 91 are disposed, thereby making it possible to set the positionalrelationship between the wirings to be the same. Therefore, it ispossible to equalize the coupling capacitance between the wirings andequalize the potential variations of the transfer gates. Therefore,influences of the potential variations of the transfer wirings becomethe same for each transfer gate, so it is possible to suppress avariation of the saturation signal amount between the photodiodes.

In addition, the dummy wiring 92 that covers the transfer wirings 84 to87 and the pulse wirings 88 to 91 is formed, thereby forming the lightshielding structure having the overlap amount 82 larger than thedistance 81 between the wirings on the pixel unit. As a result, it ispossible to prevent the hot carrier light from entering the photodiodePD of the pixel unit. The structure is particularly effective for theprevention of diagonally incident hot carrier light due to the influenceof the diffraction of light.

It should be noted that also in the first embodiment described above, apart of the dummy wiring 92 is removed, and the region where the dummywiring 92 in the upper layer and the transfer wirings 84 to 87 and thepulse wirings 88 to 91 in the lower layer do not overlap with each otheris provided, with the result that it is possible to provide an openingportion at any position.

<5. Fourth Embodiment of Solid-State Image Pickup Apparatus>

Next, the structure of a solid-state image pickup apparatus according toa fourth embodiment will be described. In the fourth embodiment, it isalso possible to apply the solid-state image pickup apparatus as in thefirst embodiment except the structure of wirings that form a lightshielding structure. Therefore, in the following, the structure of thewirings that form the light shielding structure will be described.

(Wirings: Structural Example of Light Shielding Structure)

FIGS. 9A and 9B each show a wiring structure that forms the lightshielding structure, which is provided on the pixel unit in which thepixel sharing unit is formed. FIG. 9A is a plan view showing thestructure of various wirings formed on the 4 pixel sharing unit shown inFIG. 5 mentioned above. FIG. 9B is a cross-sectional view of the wiringstructure taken along the line A-A of FIG. 9A.

In a lower wiring layer, the transfer wirings 84 to 87 and the dummywirings 92 are formed. Further, in an upper wiring layer, the pulsewirings 88 to 91 and dummy wirings 93 are formed.

In the lower wiring layer, the transfer wirings 84 to 87 and the dummywirings 92 that are extended in a horizontal direction when viewed fromabove and arranged in a vertical direction in parallel to each other aredisposed alternately at desired intervals.

In the upper wiring layer, the pulse wirings 88 to 91 and the dummywirings 93 that are extended in the horizontal direction when viewedfrom above and arranged in the vertical direction in parallel to eachother are disposed alternately at desired intervals.

The transfer wirings 84 to 87 and dummy wirings 93 and the transferwirings 84 to 87 and pulse wirings 88 to 91 respectively have theoverlap amounts 82 larger than the distance 81 between the wirings ofthe wiring layers like the wirings 40A and 40B shown in FIG. 4. In thesame way, the dummy wirings 92 and pulse wirings 88 to 91 and the dummywirings 92 and dummy wirings 93 respectively have the overlap amounts 82larger than the distance 81 between the wirings of the wiring layerslike the wirings 40A and 40B shown in FIG. 4. In this way, in the upperand lower wiring layers, the overlap amounts 82 of the wirings are eachset to be a certain length.

Further, the opening widths 83 between the transfer wirings 84 to 87 andthe dummy wirings 92 and the opening widths 83 between the pulse wirings88 to 91 and the dummy wirings 93 are each set to be a certain length.Furthermore, the intervals between the transfer wirings 84 to 87 in thelower layer and the pulse wirings 88 to 91 in the upper layer are set tobe constant.

By arranging the transfer wirings 84 to 87, the pulse wirings 88 to 91,and the dummy wirings 92 and 93 as described above, it is possible toset the positional relationship between wirings to be the same.Therefore, it is possible to equalize the coupling capacitance betweenthe wirings and equalize the potential variations of the transfer gates.As a result, the influence of the potential variations of the transferwirings become the same for each transfer gate, which can suppress avariation of the saturation signal amount between the photodiodes.

In addition, by forming the transfer wirings 84 to 87, the pulse wirings88 to 91, and the dummy wirings 92 and 93, the light shielding structurehaving the overlap amount 82 larger than the distance 81 of the wiringson the pixel unit. Thus, it is possible to prevent the hot carrier lightfrom entering the photodiodes PD of the pixel unit. The structure isparticularly effective for the prevention of diagonally incident hotcarrier light due to the influence of the diffraction of light.

As described above, in the two wiring layers which constitute the lightshielding structure, the transfer wirings 84 to 87 and the pulse wirings88 to 91 may be formed in different wiring layers. The light shieldingstructure in which the transfer wirings 84 to 87 and the pulse wirings88 to 91 are overlapped with each other may be formed. Further, thedummy wirings may be formed in both the wiring layers. By causing thedummy wirings in the upper and lower layers to be overlapped with eachother, the light shielding structure may be formed.

In this way, it is also possible to form the light shielding structureby the wirings in addition to the light shielding structure with theoverlaps of the transfer wirings 84 to 87, the pulse wirings 88 to 91with the dummy wirings 92 as in the first to third embodiments.

<6. Electronic Apparatus>

Next, a description will be given on an electronic apparatus providedwith the solid-state image pickup apparatus described above.

The solid-state image pickup apparatus is applicable to a camera systemsuch as a digital camera and a video camera, a cellular phone having animage pickup function, or an electronic apparatus such as anotherapparatus equipped with an image pickup function. In FIG. 10, as anexample of an electronic apparatus, a schematic structure in the casewhere the solid-state image pickup apparatus is applied to a cameracapable of taking a still image or a moving image will be shown.

A camera 110 in this example is provided with a solid-state image pickupapparatus 111, an optical system 112 that guides incident light to alight receiving sensor unit of the solid-state image pickup apparatus111, a shutter apparatus 113 provided between the solid-state imagepickup apparatus 111 and the optical system 112, and a drive circuit 114that drives the solid-state image pickup apparatus 111. Further, thecamera 110 is provided with a signal processing circuit 115 thatprocesses an output signal of the solid-state image pickup apparatus111.

To the solid-state image pickup apparatus 111, the solid-state imagepickup apparatus according to the first to fourth embodiments can beapplied. The optical system (optical lens) 112 forms image light(incident light) from a subject on an image pickup surface (not shown)of the solid-state image pickup apparatus 111. As a result, in thesolid-state image pickup apparatus 111, signal charges are accumulatedfor a certain time period. It should be noted that the optical system112 may be constituted of an optical lens group including a plurality ofoptical lenses. Further, the shutter apparatus 113 controls a lightirradiation time period and a light shielding time period of incidentlight with respect to the solid-state image pickup apparatus 111.

The drive circuit 114 supplies a drive signal to the solid-state imagepickup apparatus 111 and the shutter apparatus 113. Then, the drivecircuit 114 controls a signal output operation of the solid-state imagepickup apparatus 111 to the signal processing circuit 115 and a shutteroperation of the shutter apparatus 113 with the drive signal supplied.That is, in this example, with the drive signal (timing signal) suppliedfrom the drive circuit 114, a signal transfer operation from thesolid-state image pickup apparatus 111 to the signal processing circuit115 is performed.

The signal processing circuit 115 performs various signal processes fora signal transferred from the solid-state image pickup apparatus 111.The signal (image signal) that is subjected to the various signalprocesses is stored in a storage medium (not shown) such as a memory oroutput to a monitor (not shown).

By the electronic apparatus such as the camera 110, in the solid-stateimage pickup apparatus 111, it is possible to suppress a variation of asaturation signal amount along with the miniaturization of a pixel size.In addition, in the solid-state image pickup apparatus, it is alsopossible to suppress light such as hot carrier light from an activeelement such a diode and a MOS transistor at a time of an operation in aperipheral circuit unit from entering the photodiode. As a result, it ispossible to provide a high-quality electronic apparatus the imagequality of which is upgraded.

It should be noted that in the above embodiments, the example in whichthe light shielding structure is constituted of the two wiring layers isgiven, but the number of wiring layers used for the light shieldingstructure may be three or more. In this case, it is also possible toform the light shielding structure by increasing the overlap amount ofthe wirings as compared to the distance between the wirings of thewiring layers. Further, in the case where the light shielding structureis constituted of three or more layers, if the wiring width and thewiring interval are set to be uniform between thee transfer wirings andthe other wirings that constitute the light shielding structure, it isalso possible to equalize the coupling capacitance.

In addition, in the above embodiments, the case where the pixel regionand the control circuit and logic circuit are separately manufactured onthe substrates, and the substrates of those are bonded are described.However, the pixel region, the control circuit, and logic circuit may beformed in the same substrate. Further, the pixel region, the controlcircuit, and the logic circuit may not be provided in a verticaldirection and may be provided in the same plane. The present disclosurecan be applied to the case where the pixel region, the control circuit,and the logic circuit are disposed close to each other.

It should be noted that the present disclosure can take the followingconfigurations.

(1) A solid-state image pickup apparatus, including:

a pixel region in which a plurality of pixels each including aphotoelectric conversion element are arranged;

transfer wirings formed on the pixel region in parallel to each otherwith uniform opening widths; and

different wirings formed in a wiring layer above the transfer wirings,at least a part of the different wirings being overlapped with thetransfer wirings on a plan position, the transfer wirings and thedifferent wirings forming a light shielding structure in the pixelregion.

(2) The solid-state image pickup apparatus according to Item (1), inwhich

the photoelectric conversion element is provided on a first surface of asubstrate, and the wiring layer is provided on a second surface of thesubstrate.

(3) The solid-state image pickup apparatus according to Item (2),further including

a second substrate bonded to the second surface side of the substratethrough the wiring layer, in which

the second substrate includes a peripheral circuit unit, and

the light shielding structure is formed between the pixel region and theperipheral circuit unit.

(4) The solid-state image pickup apparatus according to any one of Items(1) to (3), further including

an active element configured to perform signal processing and providedclose to the photoelectric conversion element.

(5) The solid-state image pickup apparatus according to Item (4), inwhich

the active element includes at least one of a field-effect transistorand a diode.

(6) The solid-state image pickup apparatus according to any one of Items(1) to (5), in which

the different wirings include a pulse wiring and a dummy wiring.

(7) An electronic apparatus, including:

the solid-state image pickup apparatus according to any one of Items (1)to (6); and

a signal processing circuit configured to process an output signal ofthe solid-state image pickup apparatus.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2012-051427 filed in theJapan Patent Office on Mar. 8, 2012, the entire content of which ishereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A solid-state image pickup apparatus, comprising:a pixel region in which a plurality of pixels each including aphotoelectric conversion element are arranged; transfer wirings formedon the pixel region in parallel to each other with uniform openingwidths; and different wirings formed in a wiring layer above thetransfer wirings, at least a part of the different wirings beingoverlapped with the transfer wirings on a plan position, the transferwirings and the different wirings forming a light shielding structure inthe pixel region.
 2. The solid-state image pickup apparatus according toclaim 1, wherein the photoelectric conversion element is provided on afirst surface of a substrate, and the wiring layer is provided on asecond surface of the substrate.
 3. The solid-state image pickupapparatus according to claim 2, further comprising a second substratebonded to the second surface side of the substrate through the wiringlayer, wherein the second substrate includes a peripheral circuit unit,and the light shielding structure is formed between the pixel region andthe peripheral circuit unit.
 4. The solid-state image pickup apparatusaccording to claim 1, further comprising an active element configured toperform signal processing and provided close to the photoelectricconversion element.
 5. The solid-state image pickup apparatus accordingto claim 4, wherein the active element includes at least one of afield-effect transistor and a diode.
 6. The solid-state image pickupapparatus according to claim 1, wherein the different wirings include apulse wiring and a dummy wiring.
 7. An electronic apparatus, comprising:a solid-state image pickup apparatus including a pixel region in which aplurality of pixels each including a photoelectric conversion elementare arranged, transfer wirings formed on the pixel region in parallel toeach other with uniform opening widths, and different wirings formed ina wiring layer above the transfer wirings, at least a part of thedifferent wirings being overlapped with the transfer wirings on a planposition, the transfer wirings and the different wirings forming a lightshielding structure in the pixel region; and a signal processing circuitconfigured to process an output signal of the solid-state image pickupapparatus.